A generally employed objective lens driving apparatus provided in an optical pickup of the optical disc drive includes a lens holder which accommodates the objective lens, a focusing coil and a tracking coil attached to the lens holder, a supporting member for supporting a moving part which includes those coils, a yoke and magnets.
When applying driving current to the focusing coil, the electromagnetic force generated through action with the magnetic flux from the magnet brings the moving part closer to the optical disc surface, or drives the moving part in a focusing direction away from the optical disc surface. Likewise, when applying the driving current to the tracking coil, the electromagnetic force generated through action with the magnetic flux from the magnet drives the moving part in the tracking direction as the radial direction of the optical disc.
Japanese Unexamined Patent Publication No. 2009-76196 (see pages 42, 44, FIGS. 63, 65, 70) discloses the generally employed objective lens driving apparatus that needs a stopper for restricting movement of the moving part to a predetermined amount. The aforementioned document discloses the structure in which the lens holder is provided with the mechanical stopper.
Referring to FIG. 65 of Japanese Unexamined Patent Publication No. 2009-76196, the mechanical stopper is provided closer to the objective lens than the focusing coil in the focusing direction. Referring to the description in page 44 and FIG. 70 of the aforementioned document, the winding axis of the focusing coil is directed perpendicular to the optical axis of the objective lens.
Generally, the interval between the mechanical stopper and the cover for restricting the movement in the focusing direction needs to be set to a predetermined value in order to cope with deviation of the optical disc. The predetermined interval needs to be set between the cover and the optical disc in order to prevent contact therebetween.
The height of the objective lens driving apparatus in the focusing direction is set by adding height of the focusing coil disposed at the side apart from the objective lens farther than the mechanical stopper to the distance between the mechanical stopper and the cover. This may increase the height of the generally employed objective lens driving apparatus.